"Cannot use import statement outside a module" with Axios

I have a Vue.js application where two files contain:

import axios from "axios"

These files are located in src/lib within the application and include the import statement on their first line.

Running tests on Github causes Axios 1.0.0 to be installed, no matter what the package.json says, and now any test involving these files fails with the above error.

Changing the statement to const axios = require("axios") fails also; node_modules/axios/index.js contains an import statement on line 1 and the exception is thrown there.

A suggestion I've seen quite often for such issues is to add "type": "module" to package.json (which is at the same level as src/). This causes all tests to fail with a demand to rename vue.config.js as vue.config.cjs. Doing that gets me:  Error: You appear to be using a native ECMAScript module configuration file, which is only supported when running Babel asynchronously, which I do not understand.

Can anyone suggest what to do here?

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